Systems and methods for venting a water heater

ABSTRACT

Systems and methods for venting a water heater are disclosed. The system includes a water heater, a blower, a draft hood, and a thermal switch. The blower has a blower inlet positioned to receive combustion gas from the water heater and a blower outlet positioned to exhaust combustion gas. The draft hood defines a passageway positioned to receive combustion gas from the blower outlet. The draft hood defines a relief opening to allow gas to enter into or exit from the passageway of the draft hood. The thermal switch detects a blockage in the passageway of the draft hood and deactivates the water heater when a blockage is indicated. A method for venting a water heater includes blowing exhaust gas outward through a blower outlet of the water heater, and receiving the exhaust gas blown through the outlet with a draft hood positioned on top of the blower outlet.

FIELD OF THE INVENTION

The present invention relates generally to water heaters, and more particularly, to systems and methods for venting water heaters.

BACKGROUND OF THE INVENTION

Conventionally, water heaters are employed (e.g., in one or more buildings) to generate and maintain a readily-usable source of hot water for use (e.g., by the building's occupants). To generate the heat for heating the water, water heaters include a source of fuel, such as oil or natural gas, which is burned in a combustion chamber. This consumption of fuel generates exhaust gas, which must be vented from the water heater. There exists a need for improved systems and methods for venting exhaust gas from water heaters.

SUMMARY OF THE INVENTION

Aspects of the present invention are directed to systems and methods for venting a water heater.

In accordance with one aspect of the present invention, a vented water heating system is disclosed. The vented water heating system comprises a fuel-fired water heater, a blower, a draft hood, and a thermal switch. The water heater has a combustion gas exhaust outlet. The blower is positioned to advance combustion gas exhausted from the combustion gas exhaust outlet of the fuel-fired water heater. The blower has a blower inlet positioned to receive combustion gas and a blower outlet positioned to exhaust combustion gas. The draft hood defines a passageway positioned to receive combustion gas exhausted from the blower outlet. The draft hood at least partially defines a relief opening positioned to allow gas to enter into or exit from the passageway of the draft hood. The thermal switch is positioned to detect a blockage in the passageway of the draft hood and is coupled to deactivate the water heater when a blockage is indicated.

In accordance with another aspect of the present invention, a kit for venting a water heater is disclosed. The kit comprises a draft hood configured to be attached to the water heater on top of a blower outlet of the water heater. The draft hood is configured to receive the exhaust gas blown through the blower outlet.

In accordance with yet another aspect of the present invention, a method for venting a water heater is disclosed. The method comprises blowing exhaust gas outward through a blower outlet of the water heater, and receiving the exhaust gas blown through the outlet with a draft hood positioned on top of the blower outlet.

In accordance with still another aspect of the present invention, a method for configuring a vented water heating system to detect a blockage in a passageway of a draft hood is disclosed. The method comprises positioning a thermal switch downstream of a blower of the water heating system, the thermal switch positioned to detect a blockage in the passageway of the draft hood, and coupling the thermal switch to the water heating system such that the thermal switch is operable to shut down the water heating system when the thermal switch senses a temperature above a predetermined limit.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed description when read in connection with the accompanying drawings, with like elements having the same reference numerals. When a plurality of similar elements are present, a single reference numeral may be assigned to the plurality of similar elements with a small letter designation referring to specific elements. When referring to the elements collectively or to a non-specific one or more of the elements, the small letter designation may be dropped. This emphasizes that according to common practice, the various features of the drawings are not drawn to scale unless otherwise indicated. On the contrary, the dimensions of the various features may be expanded or reduced for clarity. Included in the drawings are the following figures:

FIG. 1 is a cross-sectional diagram illustrating an exemplary water heater in accordance with aspects of the present invention;

FIG. 2 is a diagram illustrating an exemplary system for venting a water heater in accordance with aspects of the present invention; and

FIG. 3 is a flow chart illustrating an exemplary method for venting a water heater in accordance with aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention relate to the ventilation of powered, atmospherically-vented water heaters. As used herein, the term “powered” in relation to ventilation refers to water heaters having a powered device, such as one or more blowers or fans, positioned to propel exhaust gas away from the combustion chamber and out of the water heater. Further, as used herein, the term “atmospherically-vented” refers to water heaters that vent exhaust gas to the atmosphere via non-positive static pressure venting.

While the systems and methods disclosed herein are described with respect to conventional water heaters, it will be understood that the invention is not limited to devices for heating water (i.e. H₂O). As used herein, the term “water heater” is intended to comprise any device adapted to generate and maintain a source of heated fluid.

Generally, the disclosed systems and methods utilize a draft hood positioned on top of the blower to improve the water heater's resistance to downdrafts. The draft hood enables the creation of negative pressure adjacent the blower outlet. The draft hood desirably includes a thermal switch coupled to the draft hood to monitor the flow of exhaust gas away from the water heater, and control operation of the water heater accordingly.

Referring now to the drawings, FIG. 1 illustrates an exemplary water heater 10 in accordance with aspects of the present invention. Water heater 10 is a powered, fuel-fired, atmospherically-vented water heater. As shown in FIG. 1, water heater 10 includes an exemplary system 100 for venting a water heater in accordance with aspects of the present invention. FIG. 2 illustrates system 100 in more detail. As a general overview, venting system 100 includes a blower 120 and a draft hood 140. Additional details of venting system 100 are described below.

Blower 120 propels exhaust gas away from the combustion chamber of water heater 10. Blower 120 includes a blower inlet 122 and a blower outlet 124. Blower 120 further includes an impeller 126 (e.g., a fan) for propelling the exhaust gas. Impeller 126 is powered by motor 128. Through operation of impeller 126, blower 120 is operable to draw exhaust gas inward from the combustion chamber through blower inlet 122, and blow the exhaust gas outward through blower outlet 124.

In an exemplary embodiment, blower 120 is positioned within a top portion of water heater 10. The size and positioning of blower inlet 122 and blower outlet 124, as well as the selection of a suitable impeller 126, may be selected based on the quantity of exhaust gas to be vented by blower 120. Suitable blowers 120 will be known to one of ordinary skill in the art from the description herein.

Draft hood 140 is positioned on top of blower outlet 124. Draft hood 140 is configured to receive the exhaust gas that is blown outward through blower outlet 124. In an exemplary embodiment, draft hood 140 includes a flared portion 142. Flared portion 142 is coupled to a pipe 144. Flared portion 142 opens toward blower outlet 124. Desirably, flared portion 142 is positioned so as to be concentric with blower outlet 124. Pipe 144 extends from the narrow end of flared portion 142 away from water heater 10.

Draft hood 140 may be mounted to blower 120 via one or more mounting structures 146. Mounting structures 146 may include bolts, screws, or any other structure adapted to affix draft hood 140 to blower 120.

As shown in FIG. 2, draft hood 140 is spaced from blower 120 by relief openings 148. Relief openings 148 enable communication of the exhaust gas blown through blower outlet 124 with the atmosphere surrounding water heater 10 and draft hood 140. This may be desirable in order to allow dilution of exhaust gas within draft hood 140, and to allow relief of any down drafts. Mounting structures 146 affix draft hood 140 at a predetermined distance from blower 120, in order to create relief openings 148 between the edge of flared portion 142 and blower 120. Mounting structures 146 may include a spacer in order to create relief openings 148 between draft hood 140 and blower 120.

Venting system 100 may further include a thermal switch 160. Thermal switch 160 is coupled to draft hood 140. Thermal switch 160 is operable to sense a temperature of the air located in relief openings 148. As will be further described herein, thermal switch 160 is calibrated to shut down (or stop the operation of) water heater 10 when thermal switch 160 is senses a temperature above a predetermined limit. Thermal switch 160 includes electrical connections 162 for connecting to, and thereby controlling the operation of, water heater 10.

As shown in FIG. 2, thermal switch 160 is directly coupled to mounting structures 146 of draft hood 140. Thermal switch 160 may employ a bracket for mounting thermal switch 160 to draft hood 140. In particular, thermal switch 160 may be positioned in relief openings 148. This position may be desirable in order to best sense the temperature of the air located in relief openings 148. In an exemplary embodiment, thermal switch 160 comprises an air temperature sensor and a memory for storing the predetermined limit. Thermal switch 160 may be a normally closed (NC) manual reset bi-metal switch. Alternatively, thermal switch 160 may be an automatic reset switch.

The operation of venting system 100 will now be described with respect to FIGS. 1 and 2. During normal operation, water heater 10 burns fuel in its combustion chamber in order to generate and maintain hot water. This burning of fuel creates exhaust gas which is vented by venting system 100. In particular, impeller 126 draws exhaust gas inward from the combustion chamber through blower inlet 122, and blows the exhaust gas outward through blower outlet 124. The exhaust gas blown outward through blower outlet 124 is received by draft hood 140. During normal operation, all of the exhaust gas flows into flared portion 142 of draft hood 140 and upward through pipe 144. When there is a vent blockage, exhaust gas may also flow outward through relief openings 148 to the atmosphere surrounding water heater 10 and draft hood 140.

During this operation, thermal switch 160 senses the temperature of the exhaust gas. Thermal switch 160 has a predetermined limit temperature. This temperature is selected based on safety concerns. The selection of a suitable predetermined limit will be known to one of ordinary skill in the art from the description herein. When thermal switch 160 senses that the air temperature in relief openings 148 exceeds the predetermined limit (for example, if the draft hood 140 were to become blocked), thermal switch 160 sends a shutdown signal to water heater 10 using electrical connections 162. Water heater 10 then stops burning fuel in the combustion chamber, and thereby, stops creating exhaust gas. Water heater 10 may stop burning fuel for a predetermined period of time, or until reset by a user of water heater 10.

The above described system may also form the basis of a kit for venting a water heater in accordance with aspects of the present invention. The kit includes a draft hood configured to be attached to a water heater on top of a blower outlet of the water heater. The draft hood is configured to receive exhaust gas blown through the blower outlet of the water heater. The draft hood of this kit may comprise any of the features described above with respect to draft hood 140.

The kit may further include a thermal switch coupled to the draft hood. The thermal switch is configured to be electrically coupled to the water heater. For example, the thermal switch may include electrical connections adapted to be connected with circuitry of the water heater. The thermal switch of this kit may comprise any of the features described above with respect to thermal switch 160.

FIG. 3 is a flow chart illustrating an exemplary method 200 for venting a water heater in accordance with aspects of the present invention. As a general overview, method 200 includes blowing exhaust gas through a blower outlet and receive the exhaust gas with a draft hood. Additional details of method 200 are described below with respect to system 100.

In step 210, exhaust gas is blown outward through a blower outlet of the water heater. In an exemplary embodiment, impeller 126 draws exhaust gas inward from the combustion chamber through blower inlet 122, and blows the exhaust gas outward through blower outlet 124.

In step 220, the exhaust gas blown outward through the blower outlet is received with a draft hood positioned on top of the blower outlet. In an exemplary embodiment, draft hood 140 is positioned to receive the exhaust gas blown outward through blower outlet 124.

Method 200 is not limited to the above steps, but may include addition steps as set forth. below.

For example, method 200 may include the step of enabling communication of the exhaust gas blown through the blower outlet with atmosphere surrounding the draft hood. In an exemplary embodiment, draft hood defines relief openings 148 between the flared portion 142 of draft hood 140 and blower 120. During a blocked vent condition, relief openings 148 may enable communication of the exhaust gas blown through blower outlet 124 with the atmosphere surrounding water heater 10 and draft hood 140.

For another example, method 200 may include the steps of sensing a temperature adjacent the draft hood with a thermal switch, and shutting down the water heater when the thermal switch senses a temperature above a predetermined limit. In an exemplary embodiment, thermal switch 160 is coupled to draft hood 140, as described above. When thermal switch 160 senses that the air temperature in relief openings 148 exceeds the predetermined limit, thermal switch 160 sends a shutdown signal to water heater 10 using electrical connections 162.

Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. 

What is claimed:
 1. A vented water heating system comprising: a fuel-fired water heater having a combustion gas exhaust outlet; a blower positioned to advance combustion gas exhausted from the combustion gas exhaust outlet of the fuel-fired water heater, the blower having a blower inlet positioned to receive combustion gas and a blower outlet positioned to exhaust combustion gas; and a draft hood defining a passageway positioned to receive combustion gas exhausted from the blower outlet, the draft hood at least partially defining a relief opening positioned to allow gas to enter into or exit from the passageway of the draft hood; and a thermal switch positioned to detect a blockage in the passageway of the draft hood and coupled to deactivate the water heater when a blockage is indicated.
 2. The system of claim 1, wherein the draft hood comprises a flared portion oriented toward the blower outlet; and the system further comprises: a pipe extending from a narrow end of the flared portion of the draft hood and in a direction generally away from the outlet of the fuel-fired water heater.
 3. The system of claim 2, wherein the flared portion of the draft hood is concentric with the blower outlet.
 4. The system of claim 1, wherein the draft hood is spaced from the blower outlet to at least partially define the relief opening and enable communication of combustion gas exhausted by the blower outlet with atmosphere surrounding the draft hood.
 5. The system of claim 1, the thermal switch being calibrated to interrupt operation of the water heater when a temperature above a predetermined limit is sensed.
 6. The system of claim 1, wherein the thermal switch is coupled to the draft hood.
 7. The system of claim 1, wherein thermal switch is positioned proximal the relief opening.
 8. A kit for venting a water heater comprising: a draft hood configured to be coupled to the water heater downstream from a blower outlet of the water heater in a direction of exhaust gas flow, the draft hood being configured to receive the exhaust gas blown through the blower outlet; and a thermal switch couplable proximal the draft hood, the thermal switch configured to be electrically coupled to the water heater, the thermal switch being calibrated to shut down the water heater when the thermal switch senses a temperature above a predetermined limit.
 9. The kit of claim 8, wherein the draft hood comprises a flared portion opening toward the blower outlet when the draft hood is attached to the water heater; and the kit further comprises: a pipe extending from a narrow end of the flared portion of the draft hood and away from the water heater when the draft hood is attached to the water heater.
 10. The kit of claim 9, wherein the flared portion is configured to be attached to the water heater concentrically with the blower outlet.
 11. The kit of claim 8, wherein the draft hood is spaced from the blower outlet by one or more relief openings when the draft hood is coupled to the water heater, the relief openings enabling communication of the exhaust gas blown through the blower outlet with atmosphere surrounding the draft hood.
 12. The system of claim 8, wherein the draft hood comprises a flared portion opening toward the blower outlet when the draft hood is attached to the water heater, and the thermal switch is directly coupled to one of the flared portion or one or more mounting structures coupled to the flared portion.
 13. The system of claim 8, wherein the draft hood is spaced from the blower outlet by one or more relief openings when the draft hood is attached to the water heater, and the thermal switch is positioned to be adjacent or within one of the relief openings.
 14. A method for venting a water heater comprising: blowing exhaust gas outward through a blower outlet of the water heater; receiving the exhaust gas blown through the outlet with a draft hood positioned downstream of the blower outlet; sensing a temperature adjacent the draft hood with a thermal switch; and deactivating the water heater when the thermal switch senses a temperature above a predetermined limit.
 15. The method of claim 14, wherein the draft hood comprises a flared portion opening toward the blower outlet, and the receiving step comprises: receiving the exhaust gas blown through the blower outlet with the flared portion of the draft hood.
 16. The method of claim 15, wherein the flared portion is positioned concentrically with the blower outlet.
 17. The method of claim 14, wherein the draft hood is spaced from the blower outlet by one or more relief openings, and the method further comprises: enabling communication of the exhaust gas blown through the blower outlet with atmosphere surrounding the draft hood via the relief openings.
 18. The method of claim 14, wherein the draft hood comprises a flared portion opening toward the blower outlet, and the sensing step comprises: sensing the temperature at a position immediately adjacent the flare portion of the draft hood.
 19. The method of claim 14, wherein the draft hood is spaced from the blower outlet by one or more relief openings, and the sensing step comprises: sensing the temperature at a position adjacent or within the relief openings.
 20. A method for configuring a vented water heating system to detect a blockage in a passageway of a draft hood, the method comprising: positioning a thermal switch downstream of a blower of the water heating system, the thermal switch being positioned to detect a blockage in the passageway of the draft hood; and coupling the thermal switch to the water heating system such that the thermal switch is operable to shut down the water heating system when the thermal switch senses a temperature above a predetermined limit. 